Different Throttle stop Screws on PDSIT

[amikulics]

Hello, I have been struggling to get my dual PDSIT carbs tuned properly on my 72 bus. I have been mainly following this: http://www.itinerant-air-cooled.com/viewtopic.php?t=7767

After all the preliminaries his first step is to adjust all the throttle stop screws. My carb setup is clearly different from the factory. The left carb has the standard throttle stop screw as described however the right side has a much larger screw (the big rusty one in the pictures) and the arm does not even have a spot for the standard stop screw. I believe the thread sizes are different on both screws so one turn of the right does not equal one turn of the left. This makes it difficult to make them 1/4 turn past touching.

So far I have just been trying to get these screws set correctly and sync the carbs, however currently it idles way too low (~500 rpm) and the only way to get the idle up is to tighten these screws. Any ideas as to what I'm doing wrong or how to adjust this setup?

link to my pictures
https://imgur.com/a/iYTVqg7

[busman78]

You need to get a Uni-Sync, along with your tachometer the amount of turns will not matter, position of the throttle plate in relation to air volume will be equal in both carbs by using a Uni-sync and tach.

By the way how stiff are those return springs, too much tension will wear out the throttle shaft bushings.

[xyzzy]

You can just do the Bentley suggested .004" (0.1mm) gap between the throttle plate and the carb body. Feeler gauge is too broad, use a drill bit or even a piece of paper. This will get you a good starting position at which point you can adjust for high speed airflow sync using the Uni-Syn with the linkage disconnected, then connect the linkage and adjust for idle.

Make sure that your retard signal from the carb is still good after doing your adjustments.
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1973 VW Westfalia 2L hydraulic, dual Solex PDSIT
1987 VW Vanagon Westfalia